Isolation and characterization of a newly discovered plant growth-promoting endophytic fungal strain from the genus Talaromyces

In the Kandi zone of Punjab, India, root and rhizospheric soil samples were collected from the local vegetation near the Shivalik mountain foothills. Fifteen fungal colonies exhibiting distinct cultural morphology on Potato Dextrose Agar (PDA) plates were selected for plant–microbe interaction studies. Among these, the isolate HNB9 was identified as a nonpathogenic root colonizer. Morphological and molecular analyses confirmed HNB9 as Talaromyces albobiverticillius, characterized by the secretion of a red pigment as a secondary metabolite. Plants colonized with T. albobiverticillius HNB9 exhibited enhanced growth, manifesting in increased shoot and root length compared to untreated controls. This study unveiled the first evidence that a species from the Talaromyces genus, specifically T. albobiverticillius, possesses dual capabilities of root colonization and plant growth promotion. Moreover, HNB9 demonstrated the production of plant growth-regulating compounds like Indole Acetic Acid (IAA) and proficient solubilization of crucial nutrients (Phosphorous, Zinc, and Silica) through plate culture methods. This finding represents a significant contribution to the understanding of root-colonizing fungi with plant growth-promoting attributes, challenging the existing knowledge gap within the Talaromyces genus.


Morphological analysis
The selected isolate's macroscopic characteristics were examined on different media and under varying growth conditions.Plates containing the isolate were incubated in darkness at 25 °C for 7 days.After this incubation period, morphological traits were recorded.The culture was then inoculated onto Potato dextrose agar (PDA), malt extract agar (MEA), Czapek yeast extract agar (CYA), CYA supplemented with 5% NaCl (CYAS), creatine sucrose agar (CREA), dichloran 18% glycerol agar (DG18), and oatmeal agar (OA) in 90 mm Petri dishes 24 .The plates were again incubated in darkness at 25 °C for 7 days.After this incubation period, colony diameters were measured, and observations were made regarding sporulation, obverse and reverse colony colors, and the presence of soluble pigments.Colony colors were identified using the color codes 25 .For the assessment of ascoma production, oatmeal agar plates were incubated for a maximum of 3 weeks.

Microscopic analysis
Confocal microscopy (CM) and scanning electron microscopy (SEM) were employed to assess the fungal ultrastructure and surface morphology.In CM, Wheat Germ Agglutinin, Alexa Fluor™ 488 Conjugate fluorescent dye (specific to fungi) was utilized to highlight spore germination and mycelial growth.Observations were made using a Nikon A1 confocal microscope at a magnification of 60× with 3× digital zoom.
To examine the ascomata and ultrastructure, the fungal mat segment (approximately 0.2 mm) consisting of spores and mycelia from a 12-day-old colony was fixed in distilled water on a small glass slide (one cm 2 area) and observed using a Nikon A1 confocal microscope at a magnification of 60× with 3× digital zoom.
For SEM analysis, a fungal mat segment (approximately 0.2 mm) comprising spores and mycelia from a 12-day-old colony was fixed in a 2.5% glutaraldehyde solution in 0.1 M phosphate saline buffer on a small glass slide (one cm 2 area).The fungal sample was then coated with gold within a vacuum chamber to enhance conductivity and examined at various magnifications.

DNA extraction, PCR amplification and sequencing
Genomic DNA was extracted from a 12-day-old culture using an in-house Fungal DNA isolation kit, and its purity and concentration were determined using a Denovix DS-11 spectrophotometer.The ITS region, as well

Sequence alignment and phylogenetic analysis
The raw sequences obtained in this study from four different loci were manually proof-read and edited using BioEdit 7.0.9 27.The edited sequences were aligned using ClustalX (v2.1) 28 and visualized using Jalview (v2.8) 29 .To ensure accurate phylogeny inference, the aligned sequences were further trimmed using GeneDoc 2.7 software.The percentage pairwise identity was computed using EBI's MUSCLE tool and presented as a Heat-Map using Morpheus software (https:// softw are.broad insti tute.org/ Morph eus).Evolutionary relationships were determined through the Maximum Likelihood (ML) method, employing the Kimura 2-parameter model.Initial tree(s) for the heuristic search were obtained by applying the Neighbor-Joining method and subjected to 500 bootstrap replications, with substitution model and rates among sites as stated in supplementary Table 2, to a matrix of pairwise distances estimated using the Maximum Composite Likelihood (MCL) approach and then selecting the topology with superior log likelihood value.The resulting tree was drawn to scale, with branch lengths representing the number of substitutions per site.Ambiguous positions were removed for each sequence pair.Evolutionary analyses were conducted using MEGA software 30 .

Plant growth promotion assay
Fungal isolate was further assessed for its ability to pertain plant growth promoting traits such as production of IAA, phosphate, zinc, and silica solubilization.

IAA production
IAA quantification was conducted following the protocol 31 .In this method, test tubes containing 10 ml of Czapek Dox medium (pH 6.5), with or without tryptophan supplementation, were inoculated with a HNB9 fungal agar plug (0.2 cm radius).The tubes were then placed in darkness and incubated at a temperature of 25 °C for a period of 15 days.After the incubation period, the culture filtrate was obtained by centrifuging the samples at 8000 rpm for 10 min.Next, 1 ml of the culture filtrate was mixed with two ml of Salkowski reagent and left to incubate in darkness for 5 min at room temperature.Optical density measurements of the prepared aliquots were taken at a wavelength of 530 nm using a UV/VIS spectrophotometer (Lab India, UV3000).The concentration of IAA was determined by comparing the obtained optical density values with a standard curve established using known concentrations of IAA.

Phosphate solubilization
Phosphate solubilization was evaluated using Pikovskaya's agar medium.Cultures were inoculated onto freshly prepared Pikovskaya's agar plates using a three-point method.The plates were then incubated for 7 days at a temperature of 25 °C.The formation of a clear zone around the fungal hyphae indicated the ability to solubilize inorganic phosphorous 32 .

Zinc solubilization
Zinc solubilization was assessed using minimal media supplemented with 0.1% zinc oxide, following the method 33 .Cultures were inoculated on the minimal media plates in a three-point pattern and incubated for 7 days at 25 °C.The presence of a clear zone around the fungal colony was observed as an indication of zinc solubilization.

Silica solubilization
Silica solubilization was assessed using Bunt and Rovira solid medium supplemented with 0.25% magnesium trisilicate, following the method 34 .Cultures were inoculated on the agar plates in a three-point pattern and incubated for 7 days at 25 °C.Observations were made to determine the formation of a clear zone around the growing fungal colony, indicating silica solubilization.

Assessment of fungal-plant interaction
The initial screening involved evaluating colony morphology and metabolite production of twelve fungal isolates.In-vitro plant-microbe interaction was conducted to further analyze these isolates.Surface sterilization of mustard seeds (Brassica juncea var.Varuna) was performed using a five % sodium hypochlorite (NaOCl) solution supplemented with 0.2% Tween20™ (one drop for 100 ml NaOCl), followed by rinsing with sterile distilled water.The seeds were then immersed in 70% ethanol for 40-50 s and washed again with distilled water.Specialized screw cap jam bottles (autoclavable) with 350 ml capacity were prepared, containing 100 ml of Murashige and Skoog media 35 slants at half strength.The surface-sterilized seeds were carefully placed on top of the slants.A fungal agar plug (0.2 cm) of the selected isolate was placed at the bottom of the slants, which were then kept in the dark at a temperature of 24 ± 2 °C.After the roots emerged (within 24-48 h), the slants were transferred to a plant tissue culture facility with a 16:8 h photoperiod (light intensity > 3500 Lux) to monitor the plant-microbe interaction.After 15 days of inoculation, the slants were evaluated to determine the pathogenicity of the fungal isolate towards the host plant.

Statistical analysis
All experiments in this study were performed in triplicate, and the results are presented as the average ± SD.Statistical analysis was conducted using STATISTICA 10.0 software (StatSoft Inc., USA).The effects of each treatment were assessed using one-way analysis of variance (ANOVA), and pairwise comparisons among the means were determined by calculating the least significant difference (LSD) with a significance level of p ≤ 0.05.

Declaration
All methods were carried out in accordance with relevant guidelines.

Results
The majority of isolated fungal colonies were identified as belonging to Aspergillus, Fusarium, and Trichoderma species based on their morphological and microscopic characteristics.Notably, one of the mixed colonies, named HNB9, exhibited a unique red color and showed highly promising results during primary in-vitro interaction studies with Mustard.

Macroscopic analysis of T. albobiverticillius HNB9
The macroscopic characteristics of the selected fungal isolate were examined under various growth conditions and on different media (Fig. 1; Table 1).On potato dextrose agar (PDA) at 25 °C for 7 days, the colonies measured 24-30 mm in diameter.They displayed white mycelia, with floccose mycelia present at the center.Exudate and soluble pigment were observed, indicating a luscious growth.Abundant green conidia were also present.The surface color ranged from white to red, while the reverse color appeared reddish brown with distinct radial furrow zonation, accompanied by dense sporulation.
On malt extract agar (MEA) at 25 °C for 7 days, the colonies measured 22-26 mm in diameter and exhibited a pinkish color due to the diffusion of exudates into the mycelia.The mycelia appeared white with a velvety texture  www.nature.com/scientificreports/overlaying floccose mycelia.Green conidia and red droplets of exudate were observed.Similar to the PDA, the surface color ranged from white to red, with a reddish-brown reverse color and the presence of concentric rings and dense sporulation.On Czapek yeast extract agar (CYA) at 25 °C for 7 days, the colonies measured 22-26 mm in diameter.The mycelia were white, exhibiting moderate sporulation.Yellow conidia, exudate, and soluble pigment were present, indicating luscious growth.The surface color ranged from white to red, and the reverse color appeared red with radial furrow zonation.
On Dichloran 18% Glycerol Agar (DG 18) at 25 °C for 7 days, the colonies measured 8-12 mm in diameter.White mycelia were observed, with floccose mycelia present at the center.However, no exudate was detected.A soluble pigment was present, and the growth was restricted.The surface color varied from white to red, while the reverse color ranged from white to brown with radial zonation and poor sporulation.
No growth was observed on CYA supplemented with five % NaCl (CYAS) at 25 °C for 7 days.On Oatmeal Agar (OMA) at 25 °C for 7 days, the colonies measured 15-18 mm in diameter and exhibited white mycelia.Sporulation was low, and the conidia appeared green.No exudate was observed, but a soluble pigment was present and the mycelial growth was restricted.The surface color ranged from white to green, and the reverse color varied from white to brown with radially furrow zonation.
On Creatine Agar (CREA) at 25 °C for 7 days, the colonies were less than 1 mm in diameter.Both the surface and reverse color were white.The growth was poor, and no sporulation occurred.

Microscopic analysis of T. albobiverticillius HNB9 ultrastructure
Under light microscopy, examination of HNB9 revealed long filamentous and septate hyphae, as well as biverticillate conidiophores that bore numerous asexual conidia when viewed at 40× magnification stained with lacto phenol cotton blue (Fig. 2a).At 100× magnification, the spores appeared globose to ellipsoidal (Fig. 2b).www.nature.com/scientificreports/ Confocal images of T. albobiverticillius HNB9 stained with fungal-specific WGA Alexa Fluor 488 dye provided further insight, showing the formation of germ tubes from the spores (Fig. 3).
Scanning electron microscopy of T. albobiverticillius HNB9 provided a closer look at the spores, which exhibited a smooth surface and varied in size between 2 and 4 µm (Fig. 5).The ultra-structures of the HNB9 conidia, as revealed by scanning electron microscopy, were spherical, with a diameter of 2.5-3.5 µm and a smooth or slightly rough surface (Fig. 5).The spores were also observed to be sickle-shaped and produced in chains.

Phylogeny and pairwise sequence comparison of T. albobiverticillius HNB9
This study explores the phylogenetic relationships and pairwise sequence comparisons of the Talaromyces albobiverticillius HNB9 isolate in comparison to 35 other Talaromyces species, categorized into sect.Talaromyces  www.nature.com/scientificreports/(11 species) and sect.Trachyspermi (24 species) (Table 2).The analysis focuses on the ITS, BenA, CaM, and RPB2 loci, providing valuable insights into the evolutionary relationships among these fungal species.The individual ITS, BenA, CaM and RPB2 datasets consist of 857, 501, 519 and 1004 characters, respectively (Table 3) and were used to study the relationship within Talaromyces.Table 4 and Fig. 6 present pairwise identity data for ITS, BenA, CaM, and RPB2 loci.For ITS, T. rubrifaciens exhibited 100% identity, while T. albobiverticillius and T. heiheensis showed high identities of 98.9% and 98.2%, respectively.In the BenA locus, T. albobiverticillius displayed the highest identity (99.77%), with T. rubrifaciens and T. erythromellis close behind.CaM locus identities ranged from 50 to 100%, with T. rubrifaciens showing the highest (97.73%).RPB2 locus identities varied from 43 to 100%, with T. rubrifaciens leading at 99.11%, followed by T. albobiverticillius.
The most optimal model for each loci used in phylogeny is listed in Supplementary Table 2.The phylogenetic tree (Fig. 7) for the ITS locus reveals that HNB9_ITS_contig is closely related to T. rubrifaciens_CGMCC 3.17658 and T_albobiverticillius_900890701, forming a distinct branch connected to T. catalonicus_FMR 16441.This suggests a recent common ancestor, with closer relatedness to T. rubrifaciens_CGMCC 3.17658 and T. albobiverticillius_900890701.
In Fig. 8, the phylogenetic tree for the BenA locus places HNB9_BenA_contig with T. rubrifaciens_CGMCC 3.17658 and T. albobiverticillius_DTO_270B8 in a subclade.The branching pattern indicates a more recent common ancestor with T. rubrifaciens_CGMCC 3.17658, suggesting a close relationship.
Figure 9 illustrates the phylogenetic tree for the CaM locus, grouping HNB9_CaM_contig with T. rubrifa-ciens_CGMCC 3.17658 under a common branch, indicating a relatively recent common ancestor.
In Fig. 10, the phylogenetic tree for the RPB2 locus groups HNB9_RPB2_contig with T. rubrifaciens_CGMCC 3.17658 and T. albobiverticillius_CBS 133440, forming a distinct clade.The short branch length suggests a closer genetic relationship between HNB9_RPB2_contig and T. rubrifaciens_CGMCC 3.17658.
The sequence data obtained from the study has been submitted to the National Center for Biotechnology Information (NCBI), and the corresponding accession numbers for the sequences are as follows: HNB9_BenA_contig: ON406962 HNB9_CaM_contig: ON406963 HNB9_RPB2_contig: ON406964 HNB9_ITS_contig: ON261679    3-6).
Furthermore, the type culture associated with the study has been submitted to the National Agriculturally Important Microbial Culture Collection (NAIMCC), which is part of the ICAR-National Bureau of Agriculturally Important Microorganisms (NBAIM) Kushmaur, Mau Nath Bhanjan Uttar Pradesh, India.The accession number assigned to the type culture is NAIMCC-SF-0025.
These accession numbers and the submission to NAIMCC provide a standardized reference for accessing and referencing the specific genetic sequences and type culture associated with the study.

Plant growth promoting (PGP) properties
T. albobiverticillius HNB9 was found to colonize plant roots and exhibit plant growth-promoting properties, leading to enhanced plant growth and development.These properties include the solubilization of zinc, phosphorus, and silica, and the production of indole-3-acetic acid (IAA), a plant growth-regulating hormone.The solubilization index for silica was determined to be 2.33, while for zinc and phosphorus, it was consistently measured at 2.33 and 2.58, respectively (Fig. 1).Furthermore, the production of IAA by T. albobiverticillius www.nature.com/scientificreports/HNB9 was quantified, and the maximum IAA production was observed to be 0.85 ± 0.02 mg/L after 12 days of incubation, with a similar level of production (0.81 ± 0.02 mg/L) maintained after 15 days of incubation (Fig. 11).These findings highlight the plant growth-promoting potential of T. albobiverticillius HNB9, which contributes to its ability to enhance plant growth and development.

Assessment of fungal-plant interaction
Our in-vitro and greenhouse studies involving mustard, maize, and okra revealed significant benefits of the fungal isolate T. albobiverticillius HNB9 on plant growth and development (Table 5).Notably, the treated okra plants exhibited remarkable improvements, including a 16.9% increase in shoot length and a 47% increase in root length compared to the non-treated control plants.Additionally, the treated plants showed enhancements in other morphological traits, with a 31.5% increase in the number of leaves and a 48.6% improvement in leaf size (Table 5).Microscopic observations further confirmed the establishment of HNB9 spores in the cortical region of the host roots, indicating successful root colonization (Fig. 12).These findings highlight the efficacy of T. albobiverticillius HNB9 in promoting plant growth and development, particularly in okra plants.

Discussion
In Stoll's study of rice and its microbial pathogens, a distinctive fungus with a tendency for producing pink exudates caught attention 36 .This fungus was later Identified as Penicillium purpureogenum by Stoll, its characterization was based on morphological traits, ultrastructure, and the unique ability to generate dark pink extracellular metabolites.The taxonomic shift occurred with the introduction of the genus Talaromyces to distinguish between Aspergillus and Penicillium species, leading to the renaming of P. purpureogenum as T.purpureogenus 37 .
The production of red pigments by Talaromyces species, including HNB9, T. albobiverticillius, and T. rubrifaciens, initially caused confusion and misidentification.However, a detailed comparison revealed that HNB9 shares more morphological similarities with T. albobiverticillius than T. rubrifaciens (Tables 6, 7).General morphological features, such as the presence of ascomata, strictly biverticillate conidiophores, and smooth-walled stipes, were more closely aligned between HNB9 and T. albobiverticillius.Despite slightly larger metulae in HNB9, the overall morphology resembled that of T. albobiverticillius, whereas T. rubrifaciens displayed distinctive characteristics 38,39 .
Further comparisons of colony morphology on different media (Tables 6, 7) reaffirmed the closer relationship between HNB9 and T. albobiverticillius.Similar growth rates, colony sizes, mycelial texture, color, and sporulation were observed in both isolates, whereas T. rubrifaciens exhibited differences in these aspects 39 .This morphological evidence strongly suggests that HNB9 is closely associated with T. albobiverticillius.
Notably, HNB9 exhibits plant growth-promoting properties absent in T. albobiverticillius or T. rubrifaciens.Confocal images stained with a fungal-specific dye (WGA Alexa Fluor 488) revealed germ tube formation from spores, indicating enhanced penetration into plant roots.This aligns with the characteristics of other plant growth-promoting fungal root endophytes like S. indica [13][14][15][16] .Furthermore, a literature review emphasized the morphological similarities between T. albobiverticillius and T. rubrifaciens, supporting the findings of the present study 38,39 .www.nature.com/scientificreports/Pairwise identity values and phylogenetic analysis suggested a close relationship and shared ancestry among T. rubrifaciens, T. albobiverticillius, T. heiheensis, and isolate HNB9.This genetic relatedness is reflected in the distinct branches or clades formed in the phylogenetic analysis, leading to the synonymization of T. rubrifaciens with T. albobiverticillius 38 .
The investigation into the red pigment produced by T. albobiverticillius revealed a complex mixture of Azaphilones, primarily found in Monascus species.Azaphilones are known for their diverse physiological    www.nature.com/scientificreports/activities, including anti-inflammatory, anticancer, and antimicrobial properties.The compounds can also react with amino acids, nucleic acids, and proteins, promoting the production of vinylogous γ-pyridones [49][50][51][52][53][54][55] .T. albobiverticillius and related species are known for producing orange, yellow, and red pigments belonging to two groups of azaphilone polyketides: mitorubrins and Monascus red pigments 56,57 .Many fungal strains naturally produce azaphilones, contributing to the distinct coloration of fungal secondary metabolites.These compounds, absent in plants, can be synthesized in significant quantities through liquid fermentation of Talaromyces or Penicillium fungal strains 58 .For instance, T. atroroseus, identified in 2013, produces red diffusible pigments containing azaphilones, mitorubrins, and Monascus pigments, excluding most mycotoxins produced by other Talaromyces species 59 .
Additionally, T. purpureogenus demonstrated the synthesis of biogenic silver nanoparticles (Tp-AgNPs) from its mycelial extract, displaying anti-proliferating, wound healing, and antibacterial properties 60 .Endophytic strains like T. assiutensis, CPEF04, isolated from the roots of the mangrove plant Avicennia marina, exhibited www.nature.com/scientificreports/anticancer and antimicrobial properties 61 .Similarly, T. flavus, isolated from the healthy leaves of the mangrove Sonneratia apetala, produced potent antitumor natural products 62 .Moreover, T. wortmanii, isolated from an endophytic strain, displayed strong antimicrobial and antiinflammatory activities 63,64 .T. radicus-Crp20, isolated from Catharanthus roseus, produced significant amounts of anticancer compounds vincristine and vinblastine in liquid cultures 65 .Various Talaromyces strains isolated from different plants exhibited polyketides with antifungal activity against plants and human pathogens 66 .
Phenolic compounds isolated from the Punica granatum fruit endophyte T. purpureogenus displayed significant activity against methicillin-resistant Staphylococcus aureus strain ATCC 700699 67 .Plant root endophytes, including Talaromyces species, contribute to plant growth, yield enhancement, and tolerance to biotic and abiotic stresses.They also produce diverse low molecular weight secondary metabolites, both in nature and in pure cultures, with potential pharmaceutical applications [68][69][70][71] .
Unlike conventional drug discovery methods, which often produce random products, plant root endophytes synthesize secondary metabolites through long-term adaptation processes for specific functions in their biotopes 72 .A new peptide termed cryptocandin, isolated from the fungal root endophyte Cryptosporiopsis quercina, exhibited excellent antimycotic activity against human pathogenic Candida albicans and Trichophyton spp. 73.Another group of antifungal compounds known as pseudomycin, isolated from plant-associated pseudomonad, was found effective against various fungi [74][75][76] .
Fungal endophytes are also studied for their production of anticancerous compounds such as Paclitaxel, isolated from the endophytic fungus T. andreanae, used to treat tissue proliferating diseases in humans 77 .Secondary metabolites from endophytic fungi tend to act against agriculturally important pests and insects.Nodulisporic acids, novel indole diterpenes isolated from the fungal endophyte Nodulisporium sp., exhibit insecticidal properties 78,79 .
The present study underscores the significance of plant root colonizing endophytes, like T. albobiverticillius HNB9, as abundant sources of genetically diverse and novel natural compounds.These compounds hold promise for addressing various human ailments and discovering treatments for currently incurable diseases.Ongoing research is focused on exploring the agro-economic aspects and the ability of T. albobiverticillius HNB9 to colonize roots, enhance crop growth, and induce biotic and abiotic stress tolerance in host plants through the secretion of various plant growth-promoting compounds.

Figure 6 .
Figure 6.Pairwise identity matrix based on the fungal isolate HNB9 multigene sequence.A colour-coded pairwise identity matrix generated from partial (a) nuclear rDNA internal transcribed spacer region (ITS), (b) BenA (β-tubulin) (c) CaM (calmodulin) and (d) RPB2 (RNA polymerase II second largest subunit) gene sequences.Each coloured cell represents the percentage identity score between two sequences.A colour key indicates the correspondence between pairwise identities and the colours displayed in the matrix.Black colour bordered box in each plot indicates the fungal isolate HNB9 used in this study and the corresponding published sequences of selected fungal species.Values on both the axes in each plot represent the fungal species and strain ID used for the comparative analysis (supplementary Tables3-6).

Figure 7 .
Figure 7. Molecular Phylogenetic analysis by Maximum Likelihood method inferred from partial ITS sequences.Bootstrap percentages ≥ 50% derived from 500 replicates are indicated at the nodes.The bar indicates the number of substitutions per position.The sequence used in this study was shown in dark red colour.Cluster specific accessions were highlighted in bold.#: sect.Talaromyces and the remaining belong to sect.Trachyspermi.

Figure 8 .
Figure 8.Molecular Phylogenetic analysis by Maximum Likelihood method inferred from partial BenA sequences.Bootstrap percentages ≥ 50% derived from 500 replicates are indicated at the nodes.The bar indicates the number of substitutions per position.Sequence used in this study was shown in dark red colour.Cluster specific accessions were highlighted in bold.#: sect.Talaromyces and the remaining belongs to sect.Trachyspermi.

Figure 9 .
Figure 9. Molecular Phylogenetic analysis by Maximum Likelihood method inferred from partial CaM sequences.Bootstrap percentages ≥ 50% derived from 500 replicates are indicated at the nodes.The bar indicates the number of substitutions per position.Sequence used in this study was shown in dark red colour.Cluster specific accessions were highlighted in bold.#: sect.Talaromyces and the remaining belong to sect.Trachyspermi.

Figure 10 .
Figure 10.Molecular Phylogenetic analysis by Maximum Likelihood method inferred from partial RPB2 sequences.Bootstrap percentages ≥ 50% derived from 500 replicates are indicated at the nodes.The bar indicates the number of substitutions per position.The sequence used in this study was shown in dark red colour.Cluster specific accessions were highlighted in bold.#: sect.Talaromyces and the remaining belong to sect.Trachyspermi.

Figure 11 .Table 5 .
Figure 11.Maximum production of IAA was observed to be 0.85 ± 0.02 and 0.81 ± 0.02 mg/l after 12 and 15 days of incubation respectively.

Table 1 .
Morphological characteristics of the fungal isolate T. albobiverticillius HNB9.N/A designates data not available.

Table 2 .
Nucleotide composition of the fungal isolate T. albobiverticillius HNB9 at four different loci.

Table 6 .
Comparison of Isolate_HNB9 with T. albobiverticillius and T. rubrifaciens on different growth media (25 °C, 7 days).N/A designates data not available.

Table 7 .
Comparative table of general morphological features of the isolate HNB9 with respect to T. albobiverticillius and T. rubrifaciens.N/A designates data not available.